Windows flash is defo not a good idea. Loads of folks that have used this metheod have screwed things up and run into all sorts of probs. Personally, i just download an .iso of the bios, burn to cd, then in my bios during post, i have the options of del for bios, esc for boot and alt+f2 for flash...Obvious one here then select the .bin file from disc if it doesnt do it automatically.
p.s. make sure you're system is stable 1st as if it hangs during flash, its a new bios chip.....
Case: Silverstone TJ07B-W, Psu: Tagan BZ-1300, Mobo: EVGA 790i Ultra, Cpu: QX9650, Ram: 4GB OCZ EB DDR3/1600, Gpu: EVGA 2xGTX 280, HD: 4x500gb Sata-300 Barracuda, DVD: Pioneer 215BK, Sound: Asus D2X/XDT, O/S: Vista Home Premium x64, Monitor: Dell 2408WFP
Loop 1: CPU/NB/SB/M.F : Rad: PA120.3, Fans: Xilence Blue Led, Res: XSPC 5.25, Pump: Ultra+EK Top, CPU: D-Tek V2, NB/SB/MF: EK
Loop 2: GPUx2 : Rad: Stealth 360, Fans: Xilence Red Wing, Res: XSPC 5.25, Pump: Ultra+EK Top, GPU: EK GPU+RAM